Loser: Barnaby Joyce (Nationals)

Mr Joyce was ruled to have been ineligible because of his dual citizenship with New Zealand, acquired because his father was born there. He will have to fight a by-election for his seat of New England on December 2.

It means the Government has lost its one-seat majority at least until after that by-election. Decisions he has taken in his ministerial roles in Agriculture and Resources could also be challenged.

His old opponent Tony Windsor has said he will not recontest the seat.

He had claimed he never believed himself to be anything other than Australian, despite being born in India to a Welsh father and only signing a form to become an Australian citizen in his late teens.

Senator Roberts' lawyers argued his case was the strongest of the seven, because he had at least made inquiries to UK authorities about his status — however comically misguided those inquiries were found to be.

His official renunciation of his British citizenship was not registered until months after the election.

Winner: Nick Xenophon (NXT)

His sub-class of UK citizenship isn't deemed to give him the rights and privileges of a British subject. He can't enter the country as a British citizen, and he also can't live there — something considered key qualities for being a foreign national. There's also the quirk that had his father waited to leave Cyprus after the island nation had declared independence from the UK, he wouldn't be covered by UK overseas citizenship.

His resignation from the Federal Parliament creates a casual vacancy and the NXT gets to choose the candidate to replace him. His staff member Rex Patrick is strongly tipped to take over the Senate seat. Mr Patrick was once a submariner in the navy and has also worked with former Liberal defence minister David Johnston.

In her resignation from politics, Kelly O'Dwyer said she feared another miscarriage in Canberra, far from home. Her announcement is shocking for more than just party-political reasons, writes Emma A. Jane.